A number of multiple filament lamp sockets and other superficially related lamp sockets have heretofore been proposed. Those of which the applicant are aware are disclosed in U.S. Pat. Nos. 2,222,655 issued Nov. 26, 1942 to Dulberg for "MULTIPLE FILAMENT LAMP COMBINATION"; 1,666,248, issued Apr. 17, 1928 to Schultz for "THREE-WAY LAMP SOCKET"; and 625,219 issued May 16, 1899 to Truitt for "ELECTRIC SWITCH"; and also, LEVITON has a switch and socket device on the market.
Each of the foregoing references discloses switching devices that are incapable of pull-chain control of a multiple filament electric lamp. The Schultz and LEVITON switch and socket mechanisms are designed only to control single filament electric lamps.
The LEVITON device has four arcuate surfaces in a circle on a non-conductive support member. Contacts are formed on two arcuate surfaces in opposing quadrants. One contact is connected to an electric power source, and the other contact is connected to the filament of a single filament electric lamp. A conductive bar rotates from an "OFF" position in which it rests on the non-conductive support member to an "ON" position in which it rests on the contacts. In the "ON" condition, current may flow from the power source, through the conductive bar, and through the filament. The filament is thus energized, and the light bulb becomes luminous. The conductive bar is rotated using a standard pull-chain type rotation actuator. The LEVITON device would energize only one filament of a standard multiple filament electric lamp.
On the other hand, Truitt and Dulberg, while allowing control of a multi-filament lamp, do not provide for control of such lamps using a pull-chain actuating device.